Improvement in rock-drills



timidi ittzt JAMES M. sTEPnnNsoN, ,or PENDLETON. INDIANA.

Letters Patent No. 113,107, dated March 28y 187i.

IMPROVEMENT IN ROCK-DRILLS.'

The Schedule referred to in these Letters Patent and making part of the same.

To all whom it may concern:

Be it known that I, JAMES M. STEPHENSON, of Pendleton, in the county o l' Madison and State of Indiana, have invented a new and useful Improvement in Rock-Drills, and I do hereby declare that the following isa full, clear, and exact description thereof,

which will enablepothers skilled in the art to make and use the same, reference being had to the accompanying drawing forming part of vthis specication.

My inventionrelates to' rock-drills, and the principle thereof consists in .giving a slight turn to the drillafter each blow upon the rock, in the manner hereinafter set forth.

I will now first proceed to describe a rock-drilling apparatus to which my improvement 1s preferably applied, and then clearly point out '-.in the claim the means which embody my invention.

In theaccompanying drawing- Figure l represents a side elevation of the drill partly in section.

Figure 2 isfa rear elevation.

Figure 3 is a detail view of the releasing-pawl lever and of the bolt, by means of which the loose-pulley or drum is converted into a windlass.

Fige 4 is a sectional. d etail of the ratcbetandpawldevices-,-by lmeans of which the drilli'sr'evolved' when' 'in operation.. .Y

Similar letters of reference indicate corresponding parts. t This drill and the apparatus by which it is operated are mounted on an upright frame, A.'

B is the drill.

C C are vertical rods, which .act as ways for guiding the drill.

D is a stationary bar attached to the frame, through which the drill passes.

E is a ratchet-plate, which slides up and down on the rods C G.

This plate is suspended by the lifting-rope Fand baiVG.

H is a collar on the drill-shaft- I is a hemispherical collar on the drill-shaft, above A the ratchetfplate E.

To the side of this hemisphere one or more ratchetpawls, J, are attached, so that they hang loosely and engage with the teeth of the ratchet-plate E.

As thedrill strikes the rock in the act of drilling, the ratchet-plate E separates fromrthe hemisphere a little space, which causes the ends of the pawlsfJ to drop down; but they are'still engaged with the teeth of-,the ratchet-plate, and,l standing at an angle as they Y do, Ythe effect when the ratchet-plate is raised is to revolve the drill, giving it a slight turn, so as to changethe position of thecritting edge at each stroke, or

every time the drillis raised.

K is the crank, and,

L the crank-shaft, by means of which the drill is operated.

M is a driving-gear wheel on the crank-shaft.

N is the drum.

O is the drum-shaft.

l? i's a gear-wheel on the drum-shaft, with which the gear-wheel M engages. I

R is a side-toothed gear-wheel, which is fast to the end of the drum.

The drum, with the gear-wheetILis loose, and revolves freely on the shaft O when the drill drops.

The drum is revolved (with the shaft) for raising the drill by means 'of the pawl-lever S, which has its fnlcrnm on the drum-shaft O, and revolves with'thatshaft and the Wheel IY.

T is a toe' on the endv oi" this pawl-lever, which engages with the teeth of the side-toothed gear R. U is a spring attached to the pawl, the end of which bears against the collar V withv a constant pressure, and serves to force vthe toe' of the lever to engage with Athe teeth of the gear It, as seen in. iig. 3.

around the drum, drops, as the drum is thus liberated *from the pavvl-lever, twice for each revolution of the drum-shaft. This, it, will be seen, is done by a continuousmotion of the cranls inone' direction.

The fall of the drill gives the drum a slight backward movement at each stroke.

The disengagement of thepawl-lever from the drum is but mmentary, or just time enough to allow the drill to drop, and that is only while the end ofthe -leveris engaged with the cam.

On the back of the drnrn there is a spring, Y, which bears with a constant pressure so as vto counteract, by the friction thus produced, the momentum of the drum in its backward movemeut.

Z is a pawl on the transverse' shaft vz', for preventing any back movement in the gear-'wheat 'P, and for locking that wheel ou either side, or preventing it from being turned except in one direction.

a is a bolt, (see iig. 3,) which is inserted through the wheel P and intov the drum, for converting the drum into a windlass by thus locking the wheel and drum together.

yIn this case the drill is detached and the windlass thus formed is used for lifting stones or for other purposes.

c represents clampsV at each end of the bar D, forkeeping that bar in place.

VIt will thus be seen that the drill makes two strokes` at each revolution of the drum-shaft, and that it is given a revolving motion at each stroke, forchanging the position-of the euttingedge;

The advantage ofmliberating and rotating a rockdrill in the manner described must be obvious to all who are acquainted with'this class of machines) Connected with' onejofthe nprights of the frame A is a ratchet-bar B' and a spring-pand G', by means of which the frame may be adjusted soas to Vstand steady Witnesses:

T. G. MITCHELL, W; O. FRAMPTON. 

